Post-acquisition effects of viruses on vector behavior are important components of manipulation strategies

A growing number of studies suggest that plant viruses manipulate host plant phenotypes to increase transmission-conducive behaviors by vectors. Studies on this phenomenon frequently omit examination of interactions that occur after vectors acquire virions, which provides an incomplete understanding of the ecology of plant virus manipulation. Here, by taking a full factorial approach that considered both the infection status of the host (Montia perfoliata) and viruliferous status of the aphid (Myzus persicae), we explored the effects of a circulative, non-propagative virus (Turnip yellows virus [TuYV]) on a suite of behavior and performance metrics that are relevant for virus transmission. Our results demonstrate that viruliferous aphids exhibited an increased velocity of movement and increased activity levels in locomotor and dispersal-retention assays. They also had increased fecundity and showed a capacity to more efficiently exploit resources by taking less time to reach the phloem and ingesting more sap, regardless of plant infection status. In contrast, non-viruliferous aphids only exhibited enhanced fecundity and biomass on TuYV-infected hosts, and had overall reduced dispersal and locomotor activity relative to viruliferous aphids. In this pathosystem, post-acquisition effects were stronger and more conducive to virus transmission than the purely pre-acquisition effects mediated by virus effects on the host plant. Our study provides additional support for the hypothesis that virus manipulation of vector behavior includes both pre- and post-acquisition effects and demonstrates the importance of considering both components when studying putative virus manipulation strategies.